Synchronous universal coupling

ABSTRACT

A synchronous universal coupling comprises inner and outer pivotal parts which are couples by a coupling member which transmits torque between the parts while enabling the parts to vary their relative angular positions with full synchronization. The coupling member is in the form of a cross with four arms at right angles to one another, two of the arms having a common bore receiving the inner pivotal part, the other arms having a common bore receiving the inner pivotal part, the other arms having aligned, spaced bores on opposite sides of the inner part receiving balls rollably engaged with respective surfaces of the inner and outer parts. The inner part may be cylindrical to fit the shape of the common bore, or alternatively the inner part may comprise a spherical portion received in the coupling member with cylindrical journals rotatable in the ends of the common bore.

United States Patent Schmid 1 June 13, 1972 SYNCHRONOUS UNIVERSALCOUPLING Primary Examiner-Edward G. Favors Auorne -Waters, Roditi,Schwartz & Nissen [72] inventor: Leopold F. Schmid, Leharstrasse 8, D y

7000 Stuttgart, 1, Germany 57] ABSTRACT [22] Filed: I971 A synchronousuniversal coupling comprises inner and outer [21] Appl. No.: 117,367pivotal parts which are couples by a coupling member which transmitstorque between the parts while enabling the parts to vary their relativeangular positions with full synchronization. [30] Foreign ApplicationPnomy Dam The coupling member is in the form of a cross with four armsAug. 12, 1970 Germany ..P 20 39 965.9 at right angles to one another,two of the arms having a common bore receiving the inner pivotal part,the other arms hav- U.S. a common'bore receiving the inner pivotal partthe other [51] f 16d 3/30 arms having aligned, spaced bores on oppositesides of the [58] Field of Search ..64/2 1 17 inner pan receiving bailsroiiabiy engaged with respective Sup faces of the inner and outer parts.The inner part may be cylin- [56] References cued drical to fit theshape of the common bore, or alternatively the UNITED STATES PATENTSinner part may comprise a spherical portion received in the couplingmember with cylindrical journals rotatable in the l Trbojevich ends ofthe common bore 3,514,973 6/1970 Kozerski. ...64/l7 3,520,152 7/1970Schmid ..64/21 5 Claims, 10 Drawing Figures SYNCI-IRONOUS UNIVERSALCOUPLING BRIEF SUMMARY OF THE INVENTION The invention relates touniversal couplings, and particularly to universal couplings in whichthe pivotal parts thereof have fully synchronized movements during theirrelative pivotal movements.

It is known to effect transmission of torque from one pivotal part tothe other using a coupling member hinge connected to one pivotal partand engaged with the other part by control members engaged in two axialgrooves in the other part.

Such a synchronous universal coupling is disclosed in US. Pat. No.2,432,395. In this synchronous universal coupling, the two pivotal partsare constructed as forks and the coupling member for transmission of thetorque from one pivotal part to the other has four arms in the form oftrunnions intersecting each other at right angles. The movements of thecoupling member permit synchronized relative movements of the twopivotal parts through control assemblies housed in axial grooves in onepivotal part. The control assemblies are diametrically opposed and eachcomprises a pin carrying a spring loaded ball movable along a curvedsurface of a plate rigidly secured to the other pivotal part.

.The aforementioned construction has the disadvantages of considerablemass, great weight, high manufacturing costs and substantial sealingdifficulties. Further drawbacks exist in its comparatively small turningangle and in the fact that it is impossible to obtain completesynchronism at all turning angles.

An object of the present invention is to provide a synchronous universalcoupling of this type but which is free from the enumerateddisadvantages.

This object is achieved according to the invention by seating thecontrol members in bores provided in the coupling member. A feature ofthe invention is that the pivotal part rigidly connected in rotation tothe coupling member, is located inside, the coupling member.Consequently, the pivotal member can be constructed as a jointed axle ofcylindrical shape with a uniform outside diameter seated in a throughbore in the coupling member. This pivotal part can also be madespherical in shape and provided with two journals-which are seated inthe bore in the coupling member.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a longitudinal sectionthrough a synchronous universal coupling in straight position of thepivotal parts;

FIG. 2 is an elevational view of the synchronous universal coupling inFIG. 1;

FIG. 3 is a transverse cross section through the synchronous universalcoupling according to FIG. 1;

FIG. 4 is a longitudinal section through the synchronous universalcoupling according to FIG. 1, but with the pivotal parts in angularposition;

FIG. 5 is a top plan view of the inner pivotal member;

FIG. 6 is a longitudinal section through a modified synchronousuniversal coupling in straight position of the pivotal parts;

FIG. 7 is an elevation view partially in section through the synchronousuniversal coupling according to FIG. 6, but with the pivotal parts inangular position;

FIG. 8 is a transverse cross section through the synchronous universalcoupling according to FIG. 6;

FIG. 9 is a top plan view of the inner pivotal part; and

FIG. 10 is a plan view partially in section of a portion of theuniversal coupling of FIG. 8.

DETAILED DESCRIPTION The synchronous universal coupling shown FIGS. 1-5is constructed as a so-called stationary coupling as used for example onthe wheel side of the front wheel drive of a motor vehicle, whileusually on the axle side a so-called sliding coupling is used, as shownfor example in FIGS. 640. In other words, in the coupling in FIGS. 1-5,the parts are coupled together for universal movement about a fixedpoint, whereas in FIGS. 6-10, the parts can additionally undergorelative axial displacement.

Referring to FIGS. 1-5, therein is shown an outer pivotal part 1 whichin the case of a front wheel drive for a motor vehicle is rigidlyconnected with a wheel, said outer part 1 being driven by a shaft 14which is rigidly connected to the inner pivotal part 6 by a splineconnection 22. The transmission of torque from the inner part 6 to theouter part 1 is effected through a coupling member 5. The member 5 is inthe form of a cross and has four arms crossing at right angles andprovided with respective bored holes. The horizontal arms 23 of member 5are provided with a common bore 13, in which is received the innerpivotal part 6. The part 6 has a uniform outside cylindrical diameter 21and is rotatable in bore 13 about axis 9 as shown in FIG. 4. Thevertically extending arms 19 of member 5 are provided with bores inwhich are seated control members 2 constructed as balls. The balls 2 aremovable on curved control surfaces 12 and 16 respectively in inner andouter pivotal parts 6 and 1, and the balls 2 govern the movements ofcoupling member 5 effecting the synchronized relative movement of thetwo pivotal parts 1 and 6. The center 8 of radius 7 to the surface 12 isoffset by the same distance from center 9 of the synchronous universalcoupling as is the center 10 of radius 4 to the surface 16 whereby theangle of traverse ll of coupling member 5 is always one-half the angleof traverse 28 of driving shaft 14 and percent synchronism is thereforeobtained for all angles of turn. The transmission of the torque fromcoupling member 5 to the outer pivotal part 1 is effected throughrollers 3 which are rotatably mounted on the vertical arms 19, and ingrooves 29 formed in the outer pivotal part 1. The outer surface 27 ofthe rollers 3 is spherical as is the bottom 17 of the grooves 29, inwhich the coupling member 5 is centered by its spherical surfaces 26.The outer pivotal part 1 is provided with notches 25 to provide accessfor the finishing operations for grooves 17, 29 and of the curvedcontrol surfaces 16 as well as the assembly and disassembly of a splitlock washer at the end of shaft 14. A rubber sleeve 15 encloses thecoupling and prevents the escape of lubricant filling the same whileprotecting the coupling against intrusion of foreign substances. Anelongate aperture 18 is provided in the coupling member 5 for thepassage of shaft 14 to permit relative pivotal movement of the parts.Recesses 24 are provided to decrease the weight of the inner pivotalpart 6.

In FIGS. 6-10 the coupling member 35 is also formed as a cross with fourarms crossing at right angles and provided with respective bores. Thehorizontal arms 36 of coupling member 35 are provided with a commonthrough hole 45 which receives two journal pins 37 rigidly connectedwith a spherical portion of inner pivotal part 34. Rollers 31 aremounted on needle bearings 32 on the vertically extending arms 41 ofcoupling member 35 and the torque is transmitted via rollers 31 togrooves 44 in the outer pivotal part 38. Sliding pans 39 are alsodisposed in grooves 44 and parts 39 have spherical inner surfaces onwhich the coupling member 35 is centered through spherical surfaces 33thereof. The sliding parts 39 are provided with passageways 42, intowhich lubricant is forced under centrifugal force. By virtue of thesliding parts 39, the inner and outer pivotal parts can be axiallydisplaced relative to one another. A tubular rivet 40 connects the twojournal pins 37 with the spherical portion of inner pivotal part 34 andit also serves to secure the shaft 30 axially.

The advantages obtained by the construction according to this inventionconsist especially in that it is possible to produce a synchronousuniversal coupling with only a few, easily manufacturable parts and thatit is able to transmit high torque with high efficiency in a smallspace. Drive tests with motor vehicles, whose front wheels were drivenby synchronous universal couplings according to the invention, haveshown that a synchronous universal coupling of the size shown in FIGS.1-5 can be used for a driving motor of metric HP performance.

Synchronous universal couplings according to this invention are small inweight, have a large turning angle and give 100 percent synchronism atall turning angles. They can be easily assembled and disassembled.

What is claimed is:

l. A universal coupling comprising inner and outer pivotal parts, andmeans joining the pivotal parts for transmitting torque therebetweenwhile enabling the parts to vary their relative angular positions, saidmeans comprising a coupling member in the form ofa cross with four armsat right angles to one another, two of said arms having a common borerotatably receiving the inner pivotal part, the other arms havingaligned spaced bores on opposite sides of said inner part, and controlmeans in said spaced bores in said other arms and engaging said pivotalparts to synchronize relative pivotal movement of said parts, saidcontrol means comprising a ball in each spaced bore rollably engagedwith respective surfaces of said parts.

2. A coupling as claimed in claim 1 wherein said inner part is locatedwholly within said coupling member, and a shaft is connected to saidinner part and extends externally of said coupling member, said couplingmember being provided with an elongate aperture permitting passage ofsaid shaft therethrough and relative pivotal movement therebetween.

3. A coupling as claimed in claim 1 wherein said inner part has acylindrical outer surface, and said common bore has a uniform diameterthrough said coupling member.

4. A coupling as claimed in claim 1 wherein said inner part comprises aspherical portion located within said coupling member and two opposedjournals pivotably mounted in said common bore.

5. A coupling as claimed in claim 1 wherein said outer pivotal part hasa groove receiving each said ball. and comprises a part axially slidablein each groove, said balls being rollable on respective of the latterparts.

1. A universal coupling comprising inner and outer pivotal parts, andmeans joining the pivotal parts for transmitting torque therebetweenwhile enabling the parts to vary their relative angular positions, saidmeans comprising a coupling member in the form of a cross with four armsat right angles to one another, two of said arms having a common borerotatably receiving the inner pivotal part, the other arms havingaligned spaced bores on opposite sides of said inner part, and controlmeans in said spaced bores in said other arms and engaging said pivotalparts to synchronize relative pivotal movement of said parts, saidcontrol means comprising a ball in each spaced bore rollably engagedwith respective surfaces of said parts.
 2. A coupling as claimed inclaim 1 wherein said inner part is located wholly within said couplingmember, and a shaft is connected to said inner part and extendsexternally of said coupling member, said coupling member being providedwith an elongate aperture permitting passage of said shaft therethroughand relative pivotal movement therebetween.
 3. A coupling as claimed inclaim 1 wherein said inner part has a cylindrical outer surface, andsaid common bore has a uniform diameter through said coupling member. 4.A coupling as claimed in claim 1 wherein said inner part comprises aspherical portion located within said coupling member and two opposedjournals pivotably mounted in said common bore.
 5. A coupling as claimedin claim 1 wherein said outer pivotal part has a groove receiving eachsaid ball, and comprises a part axially slidable in each groove, saidballs being rollable on respective of the latter parts.